// Concept utility functions, reused in conditionally-explicit
// constructors.
+ // See PR 70437, don't look at is_constructible or
+ // is_convertible if the decayed types are the same to
+ // avoid querying those properties for incomplete types.
template <typename _T1, typename _T2, typename _U1, typename _U2>
constexpr bool _ConstructiblePair()
{
- return __and_<is_constructible<_T1, const _U1&>,
- is_constructible<_T2, const _U2&>>::value;
+ return __and_<__or_<is_same<typename decay<_T1>::type,
+ typename decay<_U1>::type>,
+ is_constructible<_T1, const _U1&>>,
+ __or_<is_same<typename decay<_T2>::type,
+ typename decay<_U2>::type>,
+ is_constructible<_T2, const _U2&>>>::value;
}
template <typename _T1, typename _T2, typename _U1, typename _U2>
constexpr bool _ImplicitlyConvertiblePair()
{
- return __and_<is_convertible<const _U1&, _T1>,
- is_convertible<const _U2&, _T2>>::value;
+ return __and_<__or_<is_same<typename decay<_T1>::type,
+ typename decay<_U1>::type>,
+ is_convertible<const _U1&, _T1>>,
+ __or_<is_same<typename decay<_T2>::type,
+ typename decay<_U2>::type>,
+ is_convertible<const _U2&, _T2>>>::value;
}
template <typename _T1, typename _T2, typename _U1, typename _U2>
constexpr bool _MoveConstructiblePair()
{
- return __and_<is_constructible<_T1, _U1&&>,
- is_constructible<_T2, _U2&&>>::value;
+ return __and_<__or_<is_same<typename decay<_T1>::type,
+ typename decay<_U1>::type>,
+ is_constructible<_T1, _U1&&>>,
+ __or_<is_same<typename decay<_T2>::type,
+ typename decay<_U2>::type>,
+ is_constructible<_T2, _U2&&>>>::value;
}
template <typename _T1, typename _T2, typename _U1, typename _U2>
constexpr bool _ImplicitlyMoveConvertiblePair()
{
- return __and_<is_convertible<_U1&&, _T1>,
- is_convertible<_U2&&, _T2>>::value;
+ return __and_<__or_<is_same<typename decay<_T1>::type,
+ typename decay<_U1>::type>,
+ is_convertible<_U1&&, _T1>>,
+ __or_<is_same<typename decay<_T2>::type,
+ typename decay<_U2>::type>,
+ is_convertible<_U2&&, _T2>>>::value;
}